Abstract

A tool is disclosed for recovering a drill pipe embedded in the ground and detached from a drill string extending from the pipe to a point above ground. The tool has an upper and a lower body portion in axial alignment and a fluid chamber in the tool between the body portions. Each body portion has longitudinal cavities spaced radially about the axis of the body portions and communicate with the fluid chamber. The cavities are at acute angles to the axis of the tool the vertex of each angle being on the side of the cavity nearest the fluid chamber and each cavity having an opening at the end remote from the chamber which defines a groove along the body portion. A wedging member is positioned in each cavity and is slidable therein so that the shank of the wedging member projects laterally and outwardly from the body portion when fluid is passed into the cavities. The shank of each wedging member has a flat toothed portion from gripping the inner wall of a drill pipe. The tool is connected to the end of a drill rod and lowered down the upper drill string until the upper body portion is positioned in the upper drill string and the lower body portion is positioned in the detached drill pipe. Fluid is passed down the drill rod and into the longitudinal cavities whereby the wedging member is projected and grips the inner wall of the upper drill string and drill pipe. The drill rod upper drill string and drill pipe can then be raised from the ground.

Primary Examiner-Harvey C. Hornsby Assistant ExaminerMerle F. Maffei Attorney-William George l-lopley Feb. 1, 1972 [5 7] ABSTRACT A tool is disclosed for recovering a drill pipe embedded in the ground and detached from a drill string extending from the pipe to a point above ground. The tool has an upper and a lower body portion in axial alignment and a fluid chamber in the tool between the body portions. Each body portion has longitudinal cavities spaced radially about the axis of the body portions and communicate with the fluid chamber. The cavities are at acute angles to the axis of the tool the vertex of each angle being on the side of the cavity nearest the fluid chamber and each cavity having an opening at the end remote from the chamber which defines a groove along the body portion. A wedging member is positioned in each cavity and is slidable therein so that the shank of the wedging member projects laterally and outwardly from the body portion when fluid is passed into the cavities. The shank of each wedging member has a flat toothed portion from gripping the inner wall of a drill pipe. The tool is connected to the end of a drill rod and lowered down the upper drill string until the upper body portion is positioned in the upper drill string and the lower body portion is positioned in the detached drill pipe. Fluid is passed down the drill rod and into the longitudinal cavities whereby the wedging member is projected and grips the inner wall of the upper drill string and drill pipe. The drill rod upper drill string and drill pipe can then be raised from the ground.

, APPARATUS FOR RECOVERING A DRILL STEM portion of drill pipe which is embedded in the ground and broken or otherwise detached from a drill pipe immediately above it and extending above the ground.

The loss of a portion of a drill string in a hole involves considerable cost. In drilling operations in certain types of earth formations such as overburden, breaks in the drill stems result in adding considerably to the expense of drill operations. Because of this various attempts have been made in the past to recover such drill stems. Apparatus for recovering drill stem are sometimes known in the art as fishing tools." Such fishing tools have met with varying degrees of success.

, The method used for recovering drill stem with a fishing tool of the prior art required the removal of the portion of the drill string above the break. The fishing tool was then secured to the end of a drill string and lowered into the hole. The drill string was lowered until the fishing tool was inserted into the inner annulus of the broken drill stem. Once inside the fishing tool was attached to the drill stem by means of slips on a tapered seat or by threads on the tapered point of the fishing too]. However, when the portion of the drill string above the break is removed from the hole, the earth formations or overburden frequently fall into the hole and closes the broken end of the drill stern. This not only makes the drill stem difficult to locate but the slips or thread of the fishing tool become dirty and cannot attach itself to grip the drill stem properly. This problem is avoided by the applicants fishing tool by the nature of its construction and by reason of the fact that the drill string above the break does not have to be removed prior to lowering the applicants apparatus.

It is therefore an object of this invention to provide an improved tool for recovering a drill stem.

It'is another object of this invention to provide a tool for recovering the lower portion of a broken drill string from a drill hole without first removing the portion of the drill string above the break.

ltis another object of this invention to provide a tool for recovering the lower portion of a broken drill string which enables the drill string both above and below the break to be raised simultaneously.

These objects are obtained by a tool which comprises:

a. an upper body portion and a lower body portion in axial alignment;

b. a fluid chamber in said tool between said lower and said upper body portions;

c. each of said upper and lower body portions having a plurality of longitudinal cavities spaced radially about the axis of the upper and lower body portions and communicating with the fluid chamber;

d. said longitudinal cavities being at acute angles to the axis of said tool, the vertex of each of said angles being on the side of said longitudinal cavities nearest the fluid chamber, each of said longitudinal cavities having an opening at the end remote from said fluid chamber, said opening defining a longitudinal groove along the respective body portion;

e. wedging members each having a crown of substantially uniform cross section and a shank of bilaterally tapered cross section, one of said bilateral sides having a substantially flat toothed surface;

f. a wedging member slidable in each of said longitudinal cavities with the substantially flat toothed surface facing outwardly whereby the crown of said wedging member is positioned in said longitudinal cavity, the shank of said wedging member projecting laterally and outwardly from said body portion when the crown of said wedging member is slid away from said longitudinal cavity;

g. a connector member secured to the upper end of said tool having means for connecting said tool to a drill rod;

h. fluid passages in said connector member, said upper body portion and said lower body portion communicating with said fluid chamber whereby fluid from said drill rod may be delivered to said fluid chamber; and,

i. a driving tip secured at the lower end of said tool.

These objects are also obtained by a method which comprises:

a. lowering a hollow drill rod through the inner core of the drill pipe, said rod having a tool secured to its lower end consisting of an upper and a lower body portion in axial alignment, a fluid chamber in said tool between said upper and said lower body portions each of said body portions having a plurality oflongitudinal cavities spaced radially about the axis of the upper and lower body portions and communicating with the fluid chamber, said longitudinal cavities being at acute angles to the axis of said tool, the vertex of each of said angles being on the side of said longitudinal cavities nearest the fluid chamber, each of said longitudinal cavities having an opening at the end remote from said fluid chamber, said opening defining a longitudinal groove along the respective body portion, wedging members each having a crown of substantially uniform cross section and a shank of bilaterally tapered cross section, one of said bilateral sides having a substantially flat toothed surface, a wedging member slidable in each of said longitudinal cavities with the substantially flat toothed surface facing outwardly whereby the crown of said wedging member is positioned in said longitudinal cavity, the shank of said wedging member projecting laterally and outwardly from said body portion when the crown of said wedging member is slid away from said longitudinal cavity, a connector member secured: to and axially rotatable on the upper end of said tool comprising a flange of cross section substantially equal to the cross section of said upper body portion and means above said flange for connecting said tool to the drill rod, a plurality of grooves on said flange alignable with the openings of the longitudinal cavities in said upper body portion when said connector member is axially rotated, fluid passages in said connector member, said upper body portion and said lower body portion communicating with said fluid chamber whereby fluid from saiddrill rod may be delivered to said fluid chamber, and a driving tip secured at the lower end of said tool;

b. aligning the drill rod so that the upper body portion of said tool is in the inner core of the drill pipe above the break and the lower body portion is in the inner core of the drill pipe below the break;

c. discharging fluid through said hollow drill rod and said fluid passages thereby projecting the wedging members in the longitudinal cavities of the lower body portion downwardly and outwardly from said lower body portion and gripping the inner walls of the drill pipe below the break by means of the toothed surfaces of said wedging members;

d. rotating the drill rod and connector member of said tool so that the grooves on the connector plate are aligned with the openings of the longitudinal cavities in said upper body portion thereby permitting the shank portion of the wedging members in said longitudinal cavities to pass therethrough and project upwardly and outwardly from said upper body portion and gripping the inner wall of the drill pipe above the break by means of the toothed surfaces of said wedging members;

e. disengaging the hollow drill rod from said tool and raising the drill pipe above the break thereby raising the tool and the drill pipe below the break which is held by said tool.

In the drawings:

FIG. 1 is a perspective view of the apparatus of the present invention;

FIG. 2 is a perspective view of the upper portion of the apparatus with two sectional breaks shown for simplicity of illustration and a wedging member shown in exploded view;

FIG. 3 is a perspective view of another embodiment of a wedging member suitable in the present apparatus;

FIG. 4 is a cross-sectional elevation of one embodiment of the apparatus with one longitudinal cavity empty for purposes of illustration;

FIG. 5 is a broken section showing wedging member 9d in gripping position against an inner wall of a drill pipe;

FIG. 6 is an illustration showing the apparatus positioned between broken sections of pipe, and

FIG. 7 is a cross-sectional elevation of another embodiment of the present apparatus with a sectional break shown for simplicity of illustration.

The tool shown generally at l in FIG. 1 comprises an upper body portion 2 and a lower body portion 3 which are secured in axial alignment either by threaded connections or by welding into a single body unit. A connector member 4 is secured to and axially rotatable on the upper end of upper body portion 2. A hollow drill rod is shown in broken lines at 5 to illustrate that tool 1 can be connected to such a drill rod by means of connector member 4 for the purpose which will become apparent from the description given below. A tapered member 6 is secured to the lower end of lower body portion 3 by a threaded connection or by welding for guiding the tool into the broken end of the drill pipe.

Upper body portion 2 has a plurality of longitudinal cavities 7 having openings which define longitudinal grooves 8 along upper body portion 2 as can be seen with particular reference to FIG. 2. A wedging member 9 is slidable in each of the longitudinal cavities 7 so that their substantially flat toothed surface 10 is facing outwardly.

The wedging member 9 is shown particularly in the exploded view of the tool in FIG. 2 consists of a crown portion 11 of substantially uniform cross section and a shank portion 12 of bilaterally tapered cross section. One of the bilateral sides has a substantially flat toothed surface 10. By describing the shank as being bilaterally tapered the applicant intends to show that the shank portion 12 is tapered along two sides. One tapered side should be substantially flat and have a toothed or notched surface. This is the surface that faces outwardly when the wedging member is positioned in longitudinal cavity 7. When the wedging member is projected in the manner to be described below this substantially flat surface 10 must provide a suitable wedging surface to securely grip the interior of a drill pipe. The other side of the tapered shank should preferably be rounded or contoured in such a manner as to match the contour of the longitudinal groove 8 so that the wedging member 9 can only be slidably positioned in cavity 7 with the substantially flat toothed surface 10 facing outwardly. While some degree of tapering is permitted along the other two sides of the shank it must be appreciated that tapering along these sides to any extent reduces the surface area of surface 10 which is available for gripping.

In the embodiment shown in FIGS. 1 and 2 the substantially flat toothed surface 10 of the wedging members are aligned with the outer circumference of body portions 2 and 3. This is desirable in a tool in which the diameters of the body portions are only slightly smaller than the inner diameter of the drill pipe. For example, a tool having upper and lower body portion each having an outer diameter of 3 inches can be positioned in a pipe having an inner diameter of 3% inches and wedging members 9 need only be projected slightly to provide the wedging and gripping action necessary.

In the case where the inner diameter of the drill pipe is considerably larger than the outer diameter of the tool, a wedging member 9 as shown in FIG. 3 can be used. In this embodiment the shank portion 12 protrudes laterally from the wedging member so that when crown portion 11 is slidably positioned in longitudinal cavity 7 the substantially flat toothed surface 10 will protrude from the side of the tool. When the wedging member is projected in the manner to be described below, the surface 10 will wedge or grip the inner surface of the drill pipe. For example, wedging member 9 such as shown in FIG. 3 might be used in a tool wherein the outside diameter of the upper and lower body portions is 3 inches and the inner diameter of the pipe is 5 inches.

The crown portion 11 of the wedging members shown in FIGS. 2 and 3 have a sealing ring 13 for providing a substantially fluidtight seal when crown portion 11 is positioned in longitudinal cavity 7.

In the embodiment of the connector member 4 shown in FIG. 2 said member has a flange 14 axially positioned on the upper end of upper body portion 2 and which is of a cross section substantially equal to the cross section of body portion 2. Flange 14 has a number of grooves 15 equal to the number of longitudinal grooves 8 in upper body portion 2. These grooves are alignable with longitudinal grooves 8 by axially rotating connector member 4 so that wedging members 9 may project from the tool openings defined by longitudinal grooves 8. In the preferred embodiment of the applicant's tool, the wedging members 9 in upper body portion 2 cannot be projected from their position in longitudinal cavities 7 unless grooves 15 of plate 14 are aligned with longitudinal grooves 8. The reason for this will become apparent from the description given below with particular reference to FIG. 6. A connector means 16 is mounted above flange 14 for connecting the tool to a drill rod. In one particular embodiment of this invention the upper face of upper body portion 2 which abuts flange 14 of connector member 4 has a circular groove (not shown) into which is inserted a pin (not shown) which is flush with the top of the upper face. The flange 14 has one or more shear pins (not shown) in its lower end which are so positioned that the drill rod 5 and connector member 4 can be rotated to the extent that grooves 15 are aligned with longitudinal grooves 8. When these grooves are aligned a shear pin on the flange 14 stops against the pin in the upper face and no further rotation in that direction is permitted.

One embodiment of tool 1 can be seen in the cross section shown in FIG. 4. Upper body portion 2 and lower body portion 3 are threadedly connected in axial alignment. Longitudinal cavities 7a and 7b are shown in upper body portion 2 and longitudinal cavities 7c and 7d are shown in lower body portion 3. Cavity 7a is shown with the wedging member removed for purposes of illustration. Cavity 7a has an opening at its upper end which defines a longitudinal groove 8a along the body portion 2. Groove 8b similarly defines the opening of cavity 7b. A fluid chamber 17 is located in upper body portion 2 and fluid passages 18a and 18b place cavities 7a and 7b respectively in fluid communication with chamber 17. It can be noted that longitudinal cavities 7a and 7b are each at an acute angle to the axis of the tool so that the vertex of each of these angles is one the side of the longitudinal cavities nearest fluid chamber 17 so that a wedging member projecting from cavities 7a and 7b would be projected upwardly and outwardly.

Connector member 4 is positioned at the upper end of upper body portion 2 and the connector grooves 15 in connector plate 14 are shown aligned with longitudinal grooves 8a and 8b. A connector means 16 is shown on connector plate 14 for securing the tool to a hollow drill rod (not shown). A longitudinal fluid passage 19 in connector means 4 is aligned with longitudinal fluid passage 20 in upper body portion 2 whereby fluid such as compressed air may be delivered from a hollow drill rod connector to connector means 16 into fluid chamber 17. Fluid passages 18a and 18b are in communication with fluid chamber 17 whereby the fluid may be directed through the longitudinal cavities 7a and 7b.

Wedging members 9 are positioned in each longitudinal cavity except 7a where the wedging member was removed to show the longitudinal groove along the tool body. It can be noted that the flat toothed surface 10 of the wedging member shanks are set in the longitudinal grooves 8 and aligned with the circumference of the body portion of the tool when the heat portions of the wedging members are positioned all the way in cavities 7.

The section shown in FIG. 4 illustrates two longitudinal cavities and this figure along with the other figures of drawings imply that four such cavities are spaced radially around each of the upper and lower body portions. While the preferred embodiments described in this specification show four such cavities, three cavities radially and equidistantly spaced apart in each of said body portions would function well. While less than two such cavities in each body portion would obviously not work, no significant gripping improvement was noted in embodiments utilizing more than four cavities radially aligned in each body portion. It can also be seen that cavities 7c and 7d are at acute angles to the axis of the tool in the manner described for cavities 7a and 7bwith the vertex of their respective angles being on the side of the cavities nearest the fluid'chamber 23.

The operation of the tool will now be described with reference to FIGS. 4 and 6. When a break occurs in a drill pipe during drilling operations, the breakis usually made known to the drill operator in a very short time due to the sudden drop in pressure of thefluid delivered to the drill pipe or the sudden reduction in torque load. Sometimes the noise occasioned by the break can be heard as well.

When knowledge of a break occurs, drilling is stopped. The upper section of the drill pipe shown as 101 in FIG. 6 and located in earth formation 103 is disconnected from the driving means and held by power tongs (not shown) or other gripping means on the drilling apparatus. By upper section of drill pipe is meant that portion above break 102. At the time of stoppage, the two sections of pipe will be separated by a distance of a few inches depending on the alertness and reflexes of the operator. A hollow drill rod 5 is lowered down the center of the upper section of drill pipe with a break locating device on its lower end. A break locating device which is suitable for this purpose and is well known in the art consists generally of a cylindrical device threadedly secured at one end to the drill rod, the lower end of the device having hinged fingers kept apart by a spring that forces the fingers against the inner wall of the drill pipe. When the point of breakage is reached the fingers that had been bearing against the inner wall of the upper section of drill pipe are forced into the break area and downward progress ceases when these fingers contact the top surface of the lower section of broken drill stem.

When the location of the break is established its distance from the top of the drill hole can be measured by various means such as by marking the top section of the hollow drill rod at a point which is aligned with the top of the drill hole. The hollow drill rod is then raised and the apparatus of the present invention is secured on its lower end in place of the break locating device. The hollow drill rod is again lowered into the upper section of drill pipe to the point when the previously marked section would indicate that the apparatus at the lower end of the rod was located atthe break 102 with its upper body portion in the upper section 101 of drill pipe and the lower body portion in its lower section 104 of drill pipe. Since the recovery apparatus of this invention is generally longer than the conventional break locating device, this difference must of course be taken into account in judging the distance to the break and locating the recovery apparatus at approximately midpoint between the upper and lower sections of drill pipe.

It may be that the downward progress of the recovery apparatus is impeded by material from earth formation 103 which caved into lower section 104 of the drill pipe from the drill hole wall. For this reason the apparatus is equipped with a driving tip 6 so that the apparatus may be driven through the obstructing material until the apparatus is correctly positioned between the upper and lower sections of the drill pipe.

Fluid from drill rod 5 is passed through longitudinal passage 19 in connector member 4 shown in FIG. 4 and then into fluid chamber 17 via longitudinal passage 20. Fluid is delivered into fluid passages 18 but wedging members are held in place by the edge of plate 14. Additional fluid is delivered to fluid chamber 23 via longitudinal fluid passages 21 and 22. Fluid from chamber 23 is delivered to longitudinal cavities 7 in the lower body portion 3 via fluid passages 18. Fluid pressure forces the wedging members in the lower body portion to project downwardly and outwardly from longitudinal grooves 8 in the lower body portion until the substantially flat toothed surface 10 of these wedging members grip the interior wall of the lower section of drill pipe.

Whenthe wedging members of the lower body portion 3 are wedged in place in lower pipe section 104, the drill rod 5 is rotated until grooves 15 on connector plate 14 are aligned with the longitudinal grooves 8 in upper body portion 2. As mentioned above, this alignment may be effected when a shear pin in flange 14 abuts a pin located on the upper face of the upper body portion 2. When these grooves are aligned the fluid pressure in cavities 7 force wedging members 9 to project upwardly and outwardly from longitudinal grooves 8 in upper body portion 2 until the substantially flat toothed surface 10 of these wedging members grip the interior wall of the upper section of drill pipe 102. The sealing rings 13 on the wedging members 9 insure a substantially fluidtight seal and maintenance of fluid pressure.

When the wedging members of the upper and lower body portions are firmly wedged in place the delivery of fluid through'the hollow drill rod can be stopped. The hollow drill rod is then rotated in the direction for unscrewing the rod from therecovery tool. With the wedging members in upper body portion protruding through grooves 15 in connector flange 14 the connector member 4 is held firmly in place and does not rotate with the drill rod. The hollow drill rod is disconnected and removed from the drill pipe. The recovery tool is firmly secured in the upper and lower sections of the drill pipe thereby locking the two sections of drill pipe together. The upper section of drill pipe is raised by conventional pipe recovery means.

When the upper section 101 is raised, the recovery tool and the lower section 104 of the drill pipe is raised simultaneously. The lower section of drill pipe 104 is pulled up with the upper section by means of the firm grip of the upper and lower section by the wedging members. When the drill pipe is removed from the ground, the tool is easily released from the drill pipe by knocking the pipe in the direction towards the tool since the drill pipe is only held by the wedging action of the wedging members.

The wedging action of wedging members 9 may be more clearly understood with reference to FIG. 5 wherein the iongitudinal cavity 7d of FIG. 4 is shown. In FIG. 5 the wedging member '9 is shown projecting from the lower body portion 3 and gripping the inner wall of the lower section 104 of the drill o ipe. Thearrow in fluid passage 18d shows the direction of fluid from chamber 23 which pushes wedging member 9 out of cavity 7d to the extent whereby the substantially flat toothed surface 10 of shank portion 12 comes in contact with the interior wall of the drill pipe. The fluid is effectively sealed in by sealing ring 13 on head portion 11. In FIG. 5 the wedging member projects downwardly and outwardly to the extent generally used in normal operations of the tool, e.g., a tool body of 3-inch diameter in a drill pipe of 3% inch inside diameter.

It can be noted in FIG. 5 that the teeth on surface 10 are bevelled lto bit into the wall of the drill pipe when the tool is pulled upward. For the sake of convenience the preferred embodiment of the tool uses identical wedging members in all of the longitudinal cavities. It can be appreciated that teeth bevelled in the manner shown in FIG. 5 will also be suitable for the wedging members in upper body portion 2 and will bit into the wall of a drill pipe when the upper section of a broke drill pipesuch as item 101 shown in FIG. 6 is lifted.

The wedging members are slidably positioned in the longitudinal cavities 7 before the tool is lowered down a drill pipe. It can be seen from the drawings that these wedging members, particularly those in the lower body portion 3 can easily drop out of the tool since they are freely slidable out of cavities 7. Of course the wedging members in upper body portion 2 may be held in cavities 7 by gravity but in the preferred embodiment are also held in place by flange 14 of connector member 4. When the tool is lowered down a drill pipe a wedging member in the lower body portion 3 may drop out to the extent that the toothed surface contacts the wall of the drill pipe. This does not restrict the movement of the tool down the drill pipe however since the surface 10 easily slides over the drill pipe wall. When the lower body portion 3 of the tool is positioned in the lower section of the drill pipe as shown in 104 of FIG. 6 the teeth of the wedging members grip the walls of the drill pipe as an upward force is exerted on the tool. Even though the wedging members are otherwise free to slide out of cavities 7, the angles of the longitudinal cavities with respect to the tool body causes the wedging members to project laterally and outwardly and the lifting force is exerted on the tool thereby increasing the gripping force of the teeth against the drill pipe wall is increased.

FIG. 7 shows another embodiment of the tool of the present invention. In this embodiment the tool includes an upper body portion 202 and a lower body portion 203 in axial alignment and forming a tool body of unitary construction. A connector member 204 is secured to and axially rotatable on the upper end of upper body portion 203 and is similar to connector member 4 shown in FIGS. 1 to 6. A driving tip 206 is secured at the lower end of lower body portion 203 and is similar to driving tip 6 in the previous figures of drawings. A wall section 205 secures the upper and lower body portions and defines a fluid chamber 207 therebetween. Wall section 207 is shown in broken section since the tool may be more elongated that is shown in the drawings.

Upper and lower body portions 202 and 203 contain longitudinal cavities 208 spaced radially around their respective body portions and positioned at acute angles to the axis of the tool. The vertex of each angle is on the side of the longitudinal cavity nearest the fluid chamber. As in the embodiment shown in FIGS. 1 to 5, each of the longitudinal cavities have an opening defining a longitudinal groove along their respective body portion. Wedging members are not shown in FIG. 6 for simplicity of illustration but is must be appreciated that the wedging members described previously are also suitable in this embodiment.

Each of the longitudinal cavities has a fluid passage 209 whereby the cavities are in fluid communication with fluid chamber 207. Longitudinal passage 210 in upper body portion 202 is aligned with passage 211 in connector means 204 whereby fluid from a hollow drill rod (not shown) connected to connector means 204 may be discharged into fluid chamber 207 and then into the longitudinal cavities 208 via fluid passages 209. Wedging members in the longitudinal cavities are projected from the cavities by fluid pressure in the manner described in the previous embodiment.

I claim:

1. In combination with a drill pipe having upper and lower detached sections, a tool for recovering embedded drill pipe detached from like drill pipe extending from the top of the embedded pipe to a point above ground by lifting said embedded drill pipe from the ground together with said like drill pipes, said tool comprising:

a. an upper body portion and a lower body portion in axial alignment;

b. a fluid chamber in said tool between said lower and said upper body portions;

. each of said upper and lower body portions having a plurality of longitudinal cavities spaced radially about the axis of the upper and lower body portions and communicating with the fluid chamber;

d. said longitudinal cavities being at acute angles to the axis of said tool, the vertex of each of said angles being on the side of said longitudinal cavities nearest the fluid chamber, each of said longitudinal cavities having an opening at the end remote from said fluid chamber, said opening defining a longitudinal groove along the respective body portion;

e. wedging members each having a crown of substantially uniform cross section and a shank of bilaterally tapered cross section, one of said bilateral sides having a substantially flat toothed surface wherein said teeth are inclined in the direction of said crown;

f. one of said wedging members slidable in each of said longitudinal cavities with the substantially flat toothed surface facing outwardly whereby the crown of said wedging member is positioned in said longitudinal cavity, theshank of said wedging member projecting laterally and outwardly from said body portion when the crown of said wedging member is slid away from said longitudinal cavig. a connector member secured to the upper end of said tool having means connecting said tool to a drill rod for raising and lowering said tool;

h. fluid passages in said connector member communicating with said fluid chamber, the longitudinal cavities of said upper and lower body portions communicating with said fluid chamber whereby suflicient fluid from said drill rod may be delivered to said longitudinal cavities to project the wedging members therefrom; and

said upper body portion into gripping engagement with said upper detached pipe section and from said lower body portion into gripping engagement with said lower detached pipe section, said upper and lower detached pipe sections extending respectively axially upward and downward from said fluid chamber so that both said upper and lower detached pipe sections are simultaneously axially moved upon axial movement of said drill rod.

j. a driving tip secured at the lower end of said tool.

2. In combination with a drill pipe having upper and lower detached sections, a tool for recovering embedded drill pipe detached from like drill pipe extending from the top of the embedded pipe to a point above ground by lifting said embedded drill pipe from the ground together with said like drill pipe, said tool comprising:

a. an upper body portion and a lower body portion in axial alignment;

b. a fluid chamber in each of said upper body portions and lower body portions;

c. the upper body portion having a plurality of longitudinal cavities spaced radially about its axis and communicating with the fluid chamber in said upper body portion;

d. the lower body portion having a plurality of longitudinal cavities spaced radially about its axis and communicating with the fluid chamber in said lower body portion;

. each of the longitudinal cavities of the upper body portion and the lower body portion being at an acute angle to the axis of said tool, the vertex of each of said angles being on the side of said longitudinal cavity nearest the fluid chamber, each of said longitudinal cavities having an opening at the end remote from the fluid chambers, said opening defining a longitudinal groove along the respective body portion;

. wedging members each having a crown of substantially uniform cross section and a shank of bilaterally tapered cross section, one of said bilateral sides having a substantially flat toothed surface wherein said teeth are inclined in the direction of said crown;

g. one of said wedging members slidable on each of said longitudinal cavities with the substantially flat toothed surface facing outwardly whereby the crown of said wedging member is positioned in said longitudinal cavity, the shank of said wedging member projecting laterally and outwardly from said body portion when the crown of said wedging member is slid away from said longitudinal cavi- W;

h. a connector member secured to and axially rotatable on the upper end of said tool and comprising a plate of cross section substantially equal to the cross section of said upper body portion and means above said plate connecting said tool to a drill rod for raising and lowering said tool, a plurality of grooves on said plate alignable with the openings of the longitudinal cavities in said upper body portion when said connector member is axially rotated to permit passage therethrough of the shanks of the wedging members in said upper body portion;

. said wedging members extending simultaneously from i. fluid passages in said connector member communicating with the fluid chamber of each of said upper and said lower body portions, the longitudinal cavities of each of said upper and said lower body portions communicating with the fluid chamber of their respective body portion whereby sufficient fluid from said drill rod may be delivered to said longitudinal cavities to project the wedging members therefrom;

j. said wedging members extending simultaneously from which are aligned with the openings of the longitudinal cavities in the lower body portion to permit passage therethrough of the shanks of the wedging members in said lower body portion.

3. A tool as claimed in claim 1 wherein said driving tip is tapered and has grooves positioned around said tapered bit which are aligned with the openings of the longitudinal cavities in the lower body portion to permit passage therethrough of the shanks of the wedging members in said lower body portron.

4. A tool as claimed in claim I wherein the connector member is axially rotatable on the upper end of said tool and comprises a plate on said upper body portion and means above said plate for connecting said tool to a drill rod, a plurality of grooves on said plate alignable with the openings of the longitudinal cavities in said upper body portion when said connector member is axially rotated to permit passage therethrough of the shanks of the wedging members in said upper body portion.

Claims (4)

1. In combination with a drill pipe having upper and lower detached sections, a tool for recovering embedded drill pipe detached from like drill pipe extending from the top of the embedded pipe to a point above ground by lifting said embedded drill pipe from the ground together with said like drill pipes, said tool comprising: a. an upper body portion and a lower body portion in axial alignment; b. a fluid chamber in said tool between said lower and said upper body portions; c. each of said upper and lower body portions having a plurality of longitudinal cavities spaced radially about the axis of the upper and lower body portions and communicating with the fluid chamber; d. said longitudinal cavities being at acute angles to the axis of said tool, the vertex of each of said angles being on the side of said longitudinal cavities nearest the fluid chamber, each of said longitudinal cavities having an opening at the end remote from said fluid chamber, said opening defining a longitudinal groove along the respective body portion; e. wedging members each having a crown of substantially uniform cross section and a shank of bilaterally tapered cross section, one of said bilateral sides having a substantially flat toothed surface wherein said teeth are inclined in the direction of said crown; f. one of said wedging members slidable in each of said longitudinal cavities with the substantially flat toothed surface facinG outwardly whereby the crown of said wedging member is positioned in said longitudinal cavity, the shank of said wedging member projecting laterally and outwardly from said body portion when the crown of said wedging member is slid away from said longitudinal cavity; g. a connector member secured to the upper end of said tool having means connecting said tool to a drill rod for raising and lowering said tool; h. fluid passages in said connector member communicating with said fluid chamber, the longitudinal cavities of said upper and lower body portions communicating with said fluid chamber whereby sufficient fluid from said drill rod may be delivered to said longitudinal cavities to project the wedging members therefrom; and i. said wedging members extending simultaneously from said upper body portion into gripping engagement with said upper detached pipe section and from said lower body portion into gripping engagement with said lower detached pipe section, said upper and lower detached pipe sections extending respectively axially upward and downward from said fluid chamber so that both said upper and lower detached pipe sections are simultaneously axially moved upon axial movement of said drill rod. j. a driving tip secured at the lower end of said tool.

2. In combination with a drill pipe having upper and lower detached sections, a tool for recovering embedded drill pipe detached from like drill pipe extending from the top of the embedded pipe to a point above ground by lifting said embedded drill pipe from the ground together with said like drill pipe, said tool comprising: a. an upper body portion and a lower body portion in axial alignment; b. a fluid chamber in each of said upper body portions and lower body portions; c. the upper body portion having a plurality of longitudinal cavities spaced radially about its axis and communicating with the fluid chamber in said upper body portion; d. the lower body portion having a plurality of longitudinal cavities spaced radially about its axis and communicating with the fluid chamber in said lower body portion; e. each of the longitudinal cavities of the upper body portion and the lower body portion being at an acute angle to the axis of said tool, the vertex of each of said angles being on the side of said longitudinal cavity nearest the fluid chamber, each of said longitudinal cavities having an opening at the end remote from the fluid chambers, said opening defining a longitudinal groove along the respective body portion; f. wedging members each having a crown of substantially uniform cross section and a shank of bilaterally tapered cross section, one of said bilateral sides having a substantially flat toothed surface wherein said teeth are inclined in the direction of said crown; g. one of said wedging members slidable on each of said longitudinal cavities with the substantially flat toothed surface facing outwardly whereby the crown of said wedging member is positioned in said longitudinal cavity, the shank of said wedging member projecting laterally and outwardly from said body portion when the crown of said wedging member is slid away from said longitudinal cavity; h. a connector member secured to and axially rotatable on the upper end of said tool and comprising a plate of cross section substantially equal to the cross section of said upper body portion and means above said plate connecting said tool to a drill rod for raising and lowering said tool, a plurality of grooves on said plate alignable with the openings of the longitudinal cavities in said upper body portion when said connector member is axially rotated to permit passage therethrough of the shanks of the wedging members in said upper body portion; i. fluid passages in said connector member communicating with the fluid chamber of each of said upper and said lower body portions, the longitudinal cavities of each of said upper and said lower body portions communicating with the fluid chamber of their Respective body portion whereby sufficient fluid from said drill rod may be delivered to said longitudinal cavities to project the wedging members therefrom; j. said wedging members extending simultaneously from said upper body portion into gripping engagement with said upper detached pipe section and from said lower body portion into gripping engagement with said lower detached pipe section, said upper and lower detached pipe sections extending respectively axially upward and downward from said fluid chamber so that both said upper and lower detached pipe sections are simultaneously axially moved upon axial movement of said drill rod; and k. a tapered member at the lower end of said tool having a plurality of grooves positioned around said member and which are aligned with the openings of the longitudinal cavities in the lower body portion to permit passage therethrough of the shanks of the wedging members in said lower body portion.

3. A tool as claimed in claim 1 wherein said driving tip is tapered and has grooves positioned around said tapered bit which are aligned with the openings of the longitudinal cavities in the lower body portion to permit passage therethrough of the shanks of the wedging members in said lower body portion.

4. A tool as claimed in claim 1 wherein the connector member is axially rotatable on the upper end of said tool and comprises a plate on said upper body portion and means above said plate for connecting said tool to a drill rod, a plurality of grooves on said plate alignable with the openings of the longitudinal cavities in said upper body portion when said connector member is axially rotated to permit passage therethrough of the shanks of the wedging members in said upper body portion.